My understanding is that the reason the brain gets rotted by AI is because you do less thinking per question/problem, leading to your mind thinking less in general and getting used to that. So the solution should be to get your brain thinking more to readjust back to where it was (and beyond!).

A day or two ago in another thread someone posted these two daily brain teaser websites:

https://cluesbysam.com/

https://www.minutecryptic.com/

You could try replacing some time spent scrolling each day with solving these. Minutecryptic especially is requiring me to flex my mind in new ways.